Packet-based data networks are widely used to link various types of network elements, such as personal computers, servers, network telephones, Internet appliances, and so forth. Examples of data networks include private networks (such as local area networks or wide area networks) and public networks (such as the Internet). Common forms of communications between network elements across packet-based data networks include electronic mail, file transfer, web browsing, and other exchanges of data. More recently, with the increased capacity and reliability of packet-based data networks, audio communications (such as voice communications), video communications (such as video conferencing), and other forms of real-time interactive or streaming communications are becoming more common over packet-based data networks.
With advancements in wireless communications networks, efficient packet-based communications over wireless networks have also become possible. Traditionally, wireless communications networks have been implemented as circuit-switched networks. In a circuit-switched network, a channel between two end points (e.g., two mobile units) is occupied for the duration of the connection between the end points. Such a connection is optimal for communications that are relatively continuous, such as speech. However, circuit-switched networks are not very efficient for packet-based communications such as e-mail, web browsing, and the like.
Several packet-based wireless protocols have been proposed to provide more efficient connections between a mobile station and a packet-based data network, such as an Internet Protocol (IP) network. One such protocol is the General Packet Radio Service (GPRS) protocol, which complements existing GSM (Global System for Mobile) communications systems. Other technologies that build upon GPRS are the Enhanced GPRS (EGPRS) technology (also referred to as Enhanced Data Rate for Global Evolution or EDGE) and EGPRS COMPACT (or EDGE COMPACT) technology, which offer higher data rates and complement GSM and IS-136 systems. Another type of wireless network that can support efficient packet-based communications is a UMTS (Universal Mobile Telecommunication System) wireless network, which is based on the Wideband Code-Division Multiple Access (W-CDMA) protocol.
Voice and other forms of real-time, interactive communications over a packet-based network (wired or wireless) are sensitive to delays in, or loss of, packets. Depending upon the level of use, packet delays and rate of packet loss can vary widely in a packet-based network. Voice packets that are lost or delayed due to inadequate or unavailable capacity of a packet-based network (wired or wireless) may result in gaps, silence, and clipping of audio at the receiving end.
To ensure some level of quality of certain types of communications, such as voice or other real-time, interactive communications, quality-of-service (QoS) mechanisms can be implemented. Certain types of traffic, such as electronic mail or web browsing traffic, have relatively low QoS requirements (that is, such communications are more tolerant of transport delays and loss of packets), whereas voice and other real-time, interactive communications have relatively high QoS requirements.
However, allocation of excessive resources to voice or other real-time, interactive communications may cause performance of other types of communications to suffer, such as electronic mail or web browsing communications. On the other hand, allocating too little resources to real-time, interactive communications may cause reduced performance of such communications. As a result, a need continues to exist for a method and apparatus for balancing the needs of communications with high QoS requirements, such as real-time, interactive communications, with needs of other types of communications over a shared transport medium.